Add partial rerendering to document sheets via a custom mixin

module/apps/mixins/TAFDocumentSheetMixin.mjs

@@ -0,0 +1,36 @@
+const { hasProperty } = foundry.utils;
+
+export function TAFDocumentSheetMixin(HandlebarsApplication) {
+	class TAFDocumentSheet extends HandlebarsApplication {
+		/** @type {Record<string, string[]> | null} */
+		static PROPERTY_TO_PARTIAL = null;
+
+		/**
+		 * This override is used by the mixin in order to allow for partial
+		 * re-rendering of applications based on what properties changed.
+		 * It requires that a static PROPERTY_TO_PARTIAL to be defined as
+		 * an object of path keys to arrays of part IDs in order to work.
+		 * This will not interfere with renders that are not started as
+		 * part of the actor update lifecycle.
+		 */
+		_configureRenderOptions(options) {
+
+			if (options.renderContext === `updateActor`) {
+				const propertyToParts = this.constructor.PROPERTY_TO_PARTIAL;
+				if (propertyToParts) {
+					const parts = new Set();
+					for (const property in propertyToParts) {
+						if (hasProperty(options.renderData, property)) {
+							propertyToParts[property].forEach(partID => parts.add(partID));
+						};
+					};
+					options.parts = options.parts?.filter(part => !parts.has(part)) ?? Array.from(parts);
+				}
+			};
+
+			super._configureRenderOptions(options);
+		};
+	};
+
+	return TAFDocumentSheet;
+};